Transient FEM computation of radial force and torque for bearingless wound-rotor induction motors

This paper presents a bearingless wound-rotor induction motor. The transient responses of radial force and torque in bearingless induction motors are computed with the transient finite element method (FEM) with rotating machine models. It is shown that a steady radial force to support the shaft weight and a constant torque independent of the bearing currents can be generated at the same time. The bearingless wound-rotor induction motor is compared to the bearingless squirrel cage induction motor with respect to the transient responses of radial force and torque. A control system is proposed to implement the combination of levitation and rotation.